In order to meet the high data rate required for the next generation of cellular communication systems, the wireless industry and academia have been exploring ways to leverage the bandwidths available below-6 GHz and above-6 GHz frequencies, e.g., at centimeter wave (cmW) and millimeter wave (mmW) frequencies. The large bandwidth available at these frequencies may provide enormous capacity improvement for user-specific data transmission.
One challenge of using above-6 GHz frequencies may be characteristics related to their propagation which may be unfavorable for wireless communication, especially in an outdoor environment. For example, higher frequency transmissions may experience higher free space path loss. Rainfall and atmospheric gasses, for example, oxygen, may add further attenuation and foliage may cause attenuation and depolarization.
Narrow beam patterns, which may be used to counter these losses, may pose challenges for a base station (e.g., eNodeB) in delivering cell-specific or broadcast information. As a result, initial mmW access link system design may focus on cellular system procedures that enable add-on mmW data transmission (e.g., at least downlink transmission) to an existing network such as a small cell LTE network. Outdoor mmW cellular networks may be feasible through the use of beamforming techniques. In addition, a large number of reflected and scattered multipath components (MPC) may be utilized to facilitate the mmW coverage in non-line-of-sight (NLOS) conditions.